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Mathematical Treasure: Cardano's Acceptance of Ptolemy’s Astrology

Author(s):

Frank J. Swetz (The Pennsylvania State University)

Girolamo Cardano (1501-1576) is best remembered as a mathematician and medical doctor but, in his time, he was greatly respected and sought out as an astrologer. He had been an open critic of Ptolemy’s theories on astrology but in 1554 he changed his opinions on this matter. The title page of his book supporting Claudius Ptolemy (90-168 CE) is shown below. It bears an illustration of the author.

This image appears through the courtesy of the United States Library of Congress.